1. Field of the Invention
The present invention relates to a method of and an apparatus for editing electronic documents. More specifically, the method and the system relate to editing an electronic document in which the electronic document is circulated sequentially from one terminal to another terminal through a network with symbols. These symbols, also known as signets or signatures, represent the consent of document reviewers or editors. These symbols are sequentially added to the electronic document.
2. Description of the Prior Art
In the field of a system arranged to circulate an electronic document among a plurality of terminals through a network or an electronic mail system, several proposals have heretofore been made with respect to the protection of the entire electronic document or the prevention of forgery of the same in the course of circulation. For example, with regard to the following problems:
(1) A third party may view or destroy the contents of a document in the course of transfer of the document from one person to another person, and
(2) Another participant may edit, without permission, a document which has been approved by a certain person;
The following proposals for these problems have been made in:
(i) Computer Today, 1987/1, No. 7, pp. 38-43, and
(ii) lecture papers published in the 32nd national meeting (the first term of 1986) of Joho Shori Gakkai (Information Processing Society).
However, these problems have persisted in an electronic document editing system arranged to sequentially circulate an electronic document among a plurality of participants who can edit a document and who must consent to the amendments to the document.
In a method of circulating among participants a non-electronic document, usually in paper form, the first person upon approving the document affixes a seal or a signature representing his approval. (In the present specification, information added to a document to express approval is called an "attest pattern".) If the second person makes an addition or an amendment to the above document, he affixes his attest pattern. Normally, the addition or the amendment is handwritten. From the style of the handwritten characters, it is possible to determine how and by whom the document were amended or what portion of the contents of the document was approved by the participants.
In the editing of electronic documents, it is impossible to determine whether the contents of a document and an attest pattern which are output to a CRT screen or a printer are those of the original or a copy. As a result, if the contents of the electronic document are amended during circulation, it is impossible to determine whether approval has been obtained before or after the amendment. To prevent the contents from being amended after sealing or signing, it has heretofore been customary to design a communication system so that the documents cannot be amended during sending or receiving.
However, in general offices, it is common practice that a document can be referred to and altered by some persons before the contents have been officially authorized. Knowing who approved the document at any time in the course of reviewing would be important. There may also be a case where a document which has been approved by one reviewer is altered by another reviewer and returned to the first reviewer. In such a situation, the inability to amend the document is a severe limitation.
What is desired in the field of OA (Office Automation) is to electronically arrange a process in which a document is circulated among, and reviewed or amended by, a plurality of persons until the document is completed, thereby improving the efficiency of document creation. Each participant should be able to amend the contents of the document. Once an amendment is added, the approvals which have previously been given should be reset and the approvals of the relevant participants be again requested.